Etymology
* As an English surname, from the verb cock (“to fight, wrangle”), itself from the bird. The river in Lancashire is also from the bird.
* Also as an English surname, from the noun cock (sense 3) (“heap of hay”).
* As a German surname, Americanized from Kocher.
* The river in Cumbria is of Brythonic origin, from Proto-Brythonic *kukrā (“the crooked one”).